A standard latent-heat storage unit of the type used in a motor vehicle comprises a closed inner housing having upper and lower ends, a pack of latent-heat storage pipes or cells contained in the inner housing, and an outer housing containing the inner housing and having a floor juxtaposed with the lower inner-housing end and a top wall juxtaposed with the upper inner-housing end. The outer housing forms around the inner housing a space that is substantially empty of gas. Inlet and outlet pipes pass through the space into the inner housing so a heat-exchange fluid can be circulated through the inner housing which is otherwise effectively insulated from its surroundings by the surrounding vacuum. The confronting inner and outer surfaces of the outer and inner housings, respectively, are also normally mirrored to further thermally isolate the core.
Such a device is mass produced as described in German patent document 4,108,227. It is employed in the cooling system between the engine and the car-interior heating equipment. Typically the assembly of the finished unit is a task involving substantial manual manipulation so that it is fairly complex and expensive. Since this item is going into a product--a car or truck--that must be produced at the lowest possible unit cost, this expensive assembly operation is therefore a problem.